Milling tool



P 1940- R. B. KINZBACH 2,213,498

- MILLING TOOL Filed Aug. 6', 1957 I if,

Patented Sept. 3, 1940 ED STATES anar- MILLING TOOL Robert B. Kinzbach, Houston, Tex.

Application August 6, 1937, Serial N 0. 157,639

Claims.

operate with a whipstock set in a pipe or casing in a well whereby the pipe or casing may be perforated for the purposes hereinabove' stated.

In the drilling of wells it is not uncommon for the well to become obstructed and in such case it is often desirable to form a side opening or window in the well casing above the obstruction so that the obstruction may be side-tracked and drilling may be proceeded with through said opening to deepen the well. It is the prime object of this invention to provide a novel type of milling tool for perforating the well casing for the purpose stated.

It is another object of the invention to provide a novel form of milling tool which is soshaped that it will engage with the casing at the lower end of the perforation and be thereby held in cutting relation with the casing at the lower end of the perforation until the work has been completed in a manner hereinafter more specifically explained.

It is a further object of the invention to provide a milling tool having a novel type of cutting blade. With the above and other objects in view the invention has particular relation tocertain novel features of construction, operation and arrangement of parts an example of which is given in this specification and illustrated in the accompanying drawing wherein:

Figure 1 shows a side View of the tool partly in section shown in operative relation with the whipstock and casing which are shown in section.

Figure 2 shows a sectional view of the tool and Figure 3 shows a lower end view.

Referring now more particularly to the drawing wherein like numerals of reference designate similar parts in each of the figures, the numeral l designates the casing to be perforated in the well. The numeral 2 designates a conventional type of whipstock adapted to be set in the casing above the obstruction to be side-tracked, said whip-stock having the arcuate tapering face 3 at its upper end. The numeral 3 designates the body of the milling tool which is attached to the lower end of the operating string 5 and which is approximately cylindrical in general contour but whose upper end is upwardly tapered. The body has an axial bore 5 through which a fluid such as water may be forced onto the work.

The lower end of the body has a circular recess 1' which is preferably concentric with the bore 6 thus providing a relatively wide annular rib 8 around the outer margin of the lower end of the body 4.

The body 4 has the external longitudinal grooves 9 extending from the tapered upper end of the body to the lower end thereof and following the contour of the lower end approximately to the central bore 6.

Seated and secured in the grooves 9 are the cutting blades it which follow the contour of the grooves throughout their lengths. The outer, as well as the lower margins of these blades have the forwardly directed cutting edges H, H and these blades 80 also have the forwardly directed inner cutting edges l3 and M. These blades may be continuous, or their lower ends may be formed into separate cutters Illa as shown in Figure 2 if desired. Intermediate the blades it and seated in the side grooves 9a are the blades l5 whose lower ends do not extend across the lower end of the body to the bore 6. These blades ill have the outer and inner forwardly directed cutting edges l6 and i! and the lower end, forwardly directed, cutting edges.

In operation the milling tool is attached to the lower end of the stem 5 and lowered into the casing and into contact with the guide face 3 and is then rotated and will be held, by said guide face against the side of the casing and will gradually cut a side opening l9 therethrough which will be elongated downwardly as the work progresses, the milling tool moving gradually outwardly as it moves downwardly;

The novel shape of the milling tool at its lower end will form a projection on the casing at the lower end of the opening l9 against the inner side of which the inner sides of the cutters l0 and 15 will be in engagement and this will retain the milling tool in operative relation with the work until the perforation i9 is completed. Otherwise the tool would be deflected by the face 3 out through the opening 19 beyond the lower end thereof and out of operative relation with the work at the lower end of the opening, before the opening is completed.

The drawing and description disclose what is now considered to be a preferred form of the invention by way of illustration only, while the broad principle of the invention will be defined by the appended claims.

What I claim is:

1. A milling tool comprising an approximately cylindrical body having a depending annular rib around its lower end, side cutters on the body and spaced an approximately uniform distance apart therearound and which, at the lower end of the body, extend transversely of the body and follow the contour of the rib at the lower end of the body.

2. A milling tool comprising an approximately cylindrical body having an axial water channel therethrough, side cutters extending approximately longitudinally of the body and whose lower ends are extended radially of the body, the outer portions of the radial extensions extending downwardly further thanthe inner portions of said extensions, each side cutter and its radial extension presenting a cutting edge extending continuously from the upper end of the side cutter to the inner end of the corresponding radial extension and intermediate side outters extending approximately longitudinally of the body.

3. A milling tool comprising an approximately cylindrical body having a channel therethrough from its upper to its lower end, the central portion of the lower end of the body being recessed to provide an outside annular marginal rib, approximately longitudinal side cutters on the body and spaced approximately a uniform distance apart therearound, lower end cutters extending approximately radially inwardly toward said channel, said radially extended cutters following, approximately, the contour of the lower end of the body and their inner ends being ofiset upwardly with respect to their outer ends.

4. A milling tool comprising an approximately cylindrical body, side cutters extending approximately longitudinally of the body and whose lower ends are extending radially inwardly, the outer portions of said inwardly extended lower ends extending downwardly further than the inner portions of said inwardly extended ends, each side cutter including its inwardly extending end having a cutting edge extending continuously from the upper end of the side cutter to the inner end of said inwardly extended end, and intermediate side cutters whose lower ends terminate at approximately the same plane as the outer portions of the radial extensions.

5; A milling cutter comprising an approximately cylindrical body, side cutters extending approximately longitudinally of the body and whose lower ends are extended radially inwardly, the outer portions of said inwardly extended lower ends extending downwardly further than the inner portions of said inwardly extended ends, each side cutter including its inwardly extended end having a cutting edge extending continuously from the upper end of said side cutter downwardly along its outer margin and continuing horizontally along the lower margin of the outer portion of its inwardly extended lower end and upwardly along the inner margin of said outer portion and then horizontally across the lower margin of said inner portion.

ROBERT B. KINZBACH. 

